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Help sudden malfunction baffled


ultimatepoghero

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i have a black 84 300zx turbo. The other day i was testing my window wiper's which haven't been working. After i had no luck fixing that i went to crank the car and after starting it died in like 30 seconds. I've been running megasquirt in my car for a month with pretty much no problems maybe a hesitant start rarely. the FSM told me i had to remove the blower motor under the dash to get to the Time Control Unit to check the signal flow for the wiper motor and i had to remove that and unplug alot of things but nothing that i thought would effect the running of the car just stuff for the airconditioning. I even put all that back together and it still died after cranking. Wierd thing though is i unplugged the vacumm hose for the megasquirt from the car and the car stayed running for alot longer. I had to install megatune on a friend of mine's labtop because mine conveniently died that day to see if anything wasn't reading right on the ecu. The map reading seemed right although i still had to unplug it and increase the ve value at 101kpa so the car would stay running long enough for me to see anything and the only thing i noticed was my ego reading looked super lean. I'm not sure because when i installed megatune on my friends labtop i set it up differently than mine. the ego meter reads from 10 to 19.9 i think instead of a percent like .01 to .9 but it read all the way to the left which was lean before but if it was displaying afr then a lower number would be richer i know i probably sound like i don't know what i'm talking about i didn't set up megatune on my labtop someone else did for me and i didn't have a wideband oxygen sensor then so i might have set it up to read differenlty because now i do. I checked to make sure the injectors were firing while the car was still on the main vacumm hose for the megasquirt didn't seem like it had leaks i realy don't know why the car decided to do this all of a sudden and i feel completely in the dark please someone tell me what to do besides check everything or start over because this car is becoming realy high maintenance for me and i'm thinking about selling it so consider this an add too, i put $4000 into this car i guess that or best offer considering it doesn't run sort of, it was running great the megasquirt just needed to be tuned somemore and put on a dyno a new e-brake cable because the old one is stretched all the way and the window wiper's don't function obviously other than that i just put new shocks on it and the car is fine. please someone respond to this thread i am screwed right now.

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I checked to make sure the injectors were firing while the car was still on the main vacumm hose for the megasquirt didn't seem like it had leaks i realy don't know why the car decided to do this all of a sudden and i feel completely in the dark please someone tell me what to do besides check everthing or start over because this car is becoming realy high maintenance for me and i'm thinking about selling it so consider this an add too i put $4000 into this car i guess that or best offer considering it doesn't run sort of it was running great the megasquirt just needed to be tuned somemore and put on a dyno a new e-brake cable because the old one is stretched all the way and the window wiper's don't function obviously other than that i just put new shocks on it and the car is fine.

 

I cant personally help out,but damn that is a long sentance!!

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Dude. Punctuation. I'm not reading another post like that.

 

Lower numbers are richer if that's the way your wideband controller is programmed to display them - that's the way it is set up by default.

 

If you didn't change anything in your MS settings and it was running fine before it's probably a bad connection to one of your sensors. Check all their readings and look for one that's really wrong.

Look at the coolant, air temp, TPS, and your MAP sensor.

 

I thought I was going to have to call a tow truck once because my car started running extremely rich all of the sudden and I had to pull over. Turns out the cable to the relay board had come loose because I hadn't screwed them down (still in testing/setup phase.) Once I hooked up the laptop it was obvious the sensor grounds were disconnected and it took 20 seconds to find the problem.

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I just scanned that real quick, but everything else aside if you are able to unplug the map sensor and the car runs better then....

 

Unplugging the map sensor tells the computer the same thing as having full throttle. That means the computer will put in more fuel, so if more fuel makes it run better then you could have low fuel pressure at the rail, bad fuel pump, clogged injectors. Sounds like something with the fuel pump since you were unplugging stuff, measure the voltage at the pump. Maybe you unplugged and plugged a connection to the pump and now it is not making good contact??

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